The Copley Medal is awarded to Professor S. Chapman, F.R.S. Professor Chapman is distinguished for his contributions to many aspects of physics, astronomy and geophysics. His work on the kinetic theory of gases now forms the basis for much detailed study of gaseous phenomena, and over forty years ago his interest in these problems led him to consider the processes of diffusion and viscosity in stars. In addition to these important studies Chapman’s name has, for over half a century, been inseparably linked with problems in terrestrial magnetism and with a wide range of studies concerned with the high atmosphere, ionosphere and interplanetary space. From a statistical analysis of a great mass of data Chapman succeeded in demonstrating the existence of a small lunar component in the Earth’s quiet magnetic field variations, and he showed that the solar and lunar diurnal variations could be separated into a predominant component originating above the Earth’s surface and a subsidiary component within the Earth itself. From this standpoint he developed the general theory of the relation of the magnetic variations to the solar and lunar atmospheric tidal effects, a theory which has been fundamental to all subsequent work.
From amplitudes to gravitational radiation with cubic interactions and tidal effects